SOUTHBOROUGH, Mass. — State transportation planners are in the process of releasing proposals to reduce traffic and improve safety on Route 9 and Interstate 495 in Southborough and Westborough, particularly in the area where the two roads interchange.

Calli Cenizal, a transportation planner with MassDOT, said that the Route 9/I-495 interchange is “a high crash location in the state.” She proposed that a “braided” ramp would ease traffic along the on- and off-ramps.

Currently, drivers heading north on I-495 must choose either a westbound or eastbound exit to merge onto Route 9. Those heading west, however, must weave around drivers who enter I-495 from Route 9 just before the exit.

The braided ramp, Cenizal said, would solve the problem by allowing all drivers on I-495 to exit to Route 9 via a single ramp that later splits into both directions. A bridge would elevate one ramp over the other, easing the flow of traffic.

"The cloverleaf interchange is rapidly becoming obsolete in its design" due to increasing traffic, Cenizal said. As the surrounding area is expected to continue developing, she added that traffic is expected to continue to increase.

Cenizal estimated that such a change could be built for about $25 million within the existing area of the highway, without affecting the environment.

Cenizal discussed two more changes along Route 9. The first was a proposal to widen the road from two lanes to three between Computer Research Drive in Westborough and Deerfoot Road in Southborough. This stretch of road includes the interchange with I-495.

The second change was proposed for the area around the new Cumberland Farms on 365 Turnpike Road. "I think we can all agree that the exiting of traffic from the Red Roof Inn and Cumberland Farms onto Route 9 is a significant hazard," Cenizal said. She suggested eliminating the southbound right turn on Park Central Drive leading onto Route 9 west and making that road an entrance only. Instead, traffic leaving the gas station would travel north up Park Central Drive and turn onto a new connector leading to Flagg Road, and enter Route 9 from there.

Many Planning Board members took issue with this plan. "This is the one thing I have a question of," member Paul Cimino said, adding that drivers would be forced to enter Route 9 behind cars that would be slowing to exit—and risk rear-ending them. “I think you’re doubling your problem.”

Cenizal said MassDOT was open to feedback from the public.

Finally, she discussed proposed changes to the interchange of I-495 and I-90, which is mostly located in Hopkinton. The plan would provide additional ramp capacity by widening the I-495 southbound on-ramps into two lanes, while modifying the ramp from I-90 westbound to cross over the ramp from I-90 eastbound. A new I-495 northbound off-ramp is also being proposed.

Cenizal added, however, that the impact of the changes would depend on how the state handles tolling—a large contributor to traffic.

Cenizal said that all of MassDOT’s proposals could be advanced independently, and that “every recommendation would result in some sort of benefit.”